782 president's address. 



extends up to the very edge of the forest, where shrivelled leaves 

 and charred trunks bear testimony against the maintenance of a 

 permanent forest boundary. It is evident that the cumulative 

 effect of such fires during a succession of years must be to 

 materially extend the boundaries of the patanas at the expense 

 of the forest. Experience shows that the constant occurrence of 

 the patana fires is gradually extending the area of the patanas in 

 a westerly direction into that previously covered by forest. 

 With regard to the origin of the patanas as a whole, the cause is 

 not so clear ; there is a total absence of local tradition relating 

 to a time when the main area of the Uva patanas was in any 

 marked way different from what it is now." 



" Above 4,500 ft.,* wide tongues of patana extend in a w^esterly 

 direction up to, and in some cases over, the summit of the central 

 ridge. There can be no doubt that these extensions are due to 

 the encroachment of the Uva grass-fires into the montane wet-zone 

 forest. Upon the cleared area a herbaceous vegetation has 

 established itself, the remains of which form an accumulation of 

 sour humus which is almost uniformly present on the surface 

 above 4,500 ft. The properties of sour humus are such that 

 forest-trees can with difficulty re-establish themselves upon it. 

 It therefore follows that, apart from the effects of the present 

 annual tires, the sharp boundary, once established by fire, would 

 so gradually become irregular b}^ the advance of forest-growth 

 that only careful observations, extended over a long period, would 

 be able to detect any change. Hence has arisen the idea that 

 the present limit of the forest is a stationary one." 



A careful survey of the Dorrigo plains, which is required in 

 the interests of science, would show to what extent there is 

 similar herbaceous vegetation between the plains and the forest. 

 As regards the Dorrigo plains, the country as we know it is pro- 

 bably as it has been for many years ; in bygone years doubtless 

 the blacks fired the grass, and the white man has done the same 

 by design or accident, but apparently not to any great extent 



* In the latitude of the Dorrigo this would approximately correspond to 

 the height of the Dorrigo plains. 



